FISH LADDERPower production, in the past,
has ignored the needs of animal and plant life and we try to do things
in a much more nature friendly way! The fish ladder described is
meant for small streams and should be good for young salmonoids among others.
Small fish need small ladders. (Ideas are welcome at my email address.
My knowledge of the subject is far from complete). Please inform me if
you find a better solution.A ladder solution for shrimp and insect larvae?EmailHome
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FISH LADDER (to use approx. 200 liters per minute
of water)
Fish migration is very important. Even the smallest of fish go
up and down streams following their prey, spawning and evading
predators.
To allow small fish (7 to 15 cm) to pass the dam, a v notch
can be used. This entails having a notch in the top of the dam. It
should be a minimum of 9 cm deep and 18 cm wide. Such a notch will
allow 200 liters per minute through when the dam is full. The
water from this notch should go into a box (untreated wood) 30 to
40 cm wide, 50 cm long and 40 cm deep.
A v-notch 10 cm deep and 20 cm wide is cut in the end of this box. 2 boxes
are required for every 60 cm fall. The water from the last box should fall
into a pool or another box! at least 30 cm deep.
These sizes and depths are needed to allow the fish to rest and to
take a "run" at each jump.
For a long run, you could make the boxes all together with two long
planks at the sides, one or 2 at the bottom and the partitions at an angle
so that they are vertical when it is put in place. Netting or wire must
be placed over it to protect the fish from birds.
Perhaps your boxes can be made from large plastic containers or half
barrels. The important thing is to maintain the minimum dimensions. The
edges of the v-notches should be rounded to prevent injuries to the fish
as they do their jumps.

The fish ladder can be inset into the stream bank for stability
and leak proof operation. The exact details are up to you.
Nobody knows the perfect solution! Freshwater
shrimp and some types of aquatic insect larvae can sometimes climb over
or between several layers of cloth or sack material draped over the dam.
Perhaps they should be allowed to migrate too.